With the advent of digital media—video, audio, image, text, games and other forms of content stored and delivered in digital formats—DRM that aims to secure access to content and protect it from unauthorized use has become widely implemented. Though the methodologies DRM solutions employ may vary, the objectives of DRM are usually to increase privacy and prevent piracy, namely the unauthorized and typically illegal acquisition of copyrighted or confidential content; to attempt to ensure that the content that is being monetized is not consumed (for example viewed, listened to, played or read) without collecting payment from the consumer; to attempt to ensure that content is used within the constraints (often licensing terms) stipulated by the content owner; and to maintain a record of the identity of the original content holder (i.e., a licensee of content, or a buyer of content) for a particular piece of content, even if the content asset has been pirated, to facilitate investigation and prosecution of the pirates of the content.
A single DRM product or a group of DRM products may be used in conjunction with one another to protect content during all of the below stages in the digital-media distribution process:
1.) While media is stored in a media source; 2.) While media is being delivered from a media source to a media player (one example of this is media that is being transmitted from a media server to a media player over a network, such as the Internet); and 3.) While media is processed by the media player and delivered to a display device. A display device may be a monitor, a screen, a television, a projector, a personal computer, a smartphone or any other hardware that permits a user to play media.
Media remains vulnerable to piracy and other forms of unauthorized use while it is being transmitted to a screen (or some other device that transmits content for a user's perception), because the media is in an unencrypted format when it is being transmitted to the screen.
The “analog hole” or the “analog loophole” is one example of the media's vulnerability during its transmission to a screen. The “analog hole” refers to digital media's vulnerability to piracy when it is decoded while it is being transmitted to a display device by a decoder (from the digital format in which it was previously encoded). Another example of this type of vulnerability can also be seen in digital formats, such the HDMI format which is often used to provide media data to display devices. HDMI utilizes digital data, but it is still susceptible to the type of unauthorized use noted above. Malicious users may try to make a copy of the media content after the media content has been decrypted in preparation for being displayed on the display device. These two examples of vulnerability are not exclusive, and there are other such examples.
The present invention recognizes such vulnerably of media data, whether it is video or audio data, just prior to being presented to a user on a visual display device and/or an audio reproducing device, and proposes a number of approaches to monitor and protect content after it has been decrypted (or otherwise stripped of protective measures) and is being transmitted to the visual display device and/or audio reproducing device.